src/compiler/nir/nir_lower_system_values.c

   1 /*
   2  * Copyright © 2014 Intel Corporation
   3  *
   4  * Permission is hereby granted, free of charge, to any person obtaining a
   5  * copy of this software and associated documentation files (the "Software"),
   6  * to deal in the Software without restriction, including without limitation
   7  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
   8  * and/or sell copies of the Software, and to permit persons to whom the
   9  * Software is furnished to do so, subject to the following conditions:
  10  *
  11  * The above copyright notice and this permission notice (including the next
  12  * paragraph) shall be included in all copies or substantial portions of the
  13  * Software.
  14  *
  15  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  16  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  17  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  18  * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
  19  * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
  20  * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
  21  * IN THE SOFTWARE.
  22  *
  23  * Authors:
  24  *    Connor Abbott (cwabbott0@gmail.com)
  25  *
  26  */
  27
  28 #include "nir.h"
  29 #include "nir_builder.h"
  30
  31 struct lower_system_values_state {
  32    nir_builder builder;
  33    bool progress;
  34 };
  35
  36 static bool
  37 convert_block(nir_block *block, void *void_state)
  38 {
  39    struct lower_system_values_state *state = void_state;
  40
  41    nir_builder *b = &state->builder;
  42
  43    nir_foreach_instr_safe(block, instr) {
  44       if (instr->type != nir_instr_type_intrinsic)
  45          continue;
  46
  47       nir_intrinsic_instr *load_var = nir_instr_as_intrinsic(instr);
  48
  49       if (load_var->intrinsic != nir_intrinsic_load_var)
  50          continue;
  51
  52       nir_variable *var = load_var->variables[0]->var;
  53       if (var->data.mode != nir_var_system_value)
  54          continue;
  55
  56       b->cursor = nir_after_instr(&load_var->instr);
  57
  58       nir_ssa_def *sysval;
  59       switch (var->data.location) {
  60       case SYSTEM_VALUE_GLOBAL_INVOCATION_ID: {
  61          /* From the GLSL man page for gl_GlobalInvocationID:
  62           *
  63           *    "The value of gl_GlobalInvocationID is equal to
  64           *    gl_WorkGroupID * gl_WorkGroupSize + gl_LocalInvocationID"
  65           */
  66
  67          nir_const_value local_size;
  68          local_size.u[0] = b->shader->info.cs.local_size[0];
  69          local_size.u[1] = b->shader->info.cs.local_size[1];
  70          local_size.u[2] = b->shader->info.cs.local_size[2];
  71
  72          nir_ssa_def *group_id =
  73             nir_load_system_value(b, nir_intrinsic_load_work_group_id, 0);
  74          nir_ssa_def *local_id =
  75             nir_load_system_value(b, nir_intrinsic_load_local_invocation_id, 0);
  76
  77          sysval = nir_iadd(b, nir_imul(b, group_id,
  78                                           nir_build_imm(b, 3, local_size)),
  79                               local_id);
  80          break;
  81       }
  82
  83       case SYSTEM_VALUE_LOCAL_INVOCATION_INDEX: {
  84          /* From the GLSL man page for gl_LocalInvocationIndex:
  85           *
  86           *    ?The value of gl_LocalInvocationIndex is equal to
  87           *    gl_LocalInvocationID.z * gl_WorkGroupSize.x *
  88           *    gl_WorkGroupSize.y + gl_LocalInvocationID.y *
  89           *    gl_WorkGroupSize.x + gl_LocalInvocationID.x"
  90           */
  91          nir_ssa_def *local_id =
  92             nir_load_system_value(b, nir_intrinsic_load_local_invocation_id, 0);
  93
  94          unsigned stride_y = b->shader->info.cs.local_size[0];
  95          unsigned stride_z = b->shader->info.cs.local_size[0] *
  96                              b->shader->info.cs.local_size[1];
  97
  98          sysval = nir_iadd(b, nir_imul(b, nir_channel(b, local_id, 2),
  99                                           nir_imm_int(b, stride_z)),
 100                               nir_iadd(b, nir_imul(b, nir_channel(b, local_id, 1),
 101                                                       nir_imm_int(b, stride_y)),
 102                                           nir_channel(b, local_id, 0)));
 103          break;
 104       }
 105
 106       case SYSTEM_VALUE_VERTEX_ID:
 107          if (b->shader->options->vertex_id_zero_based) {
 108             sysval = nir_iadd(b,
 109                nir_load_system_value(b, nir_intrinsic_load_vertex_id_zero_base, 0),
 110                nir_load_system_value(b, nir_intrinsic_load_base_vertex, 0));
 111          } else {
 112             sysval = nir_load_system_value(b, nir_intrinsic_load_vertex_id, 0);
 113          }
 114          break;
 115
 116       case SYSTEM_VALUE_INSTANCE_INDEX:
 117          sysval = nir_iadd(b,
 118             nir_load_system_value(b, nir_intrinsic_load_instance_id, 0),
 119             nir_load_system_value(b, nir_intrinsic_load_base_instance, 0));
 120          break;
 121
 122       default: {
 123          nir_intrinsic_op sysval_op =
 124             nir_intrinsic_from_system_value(var->data.location);
 125          sysval = nir_load_system_value(b, sysval_op, 0);
 126          break;
 127       } /* default */
 128       }
 129
 130       nir_ssa_def_rewrite_uses(&load_var->dest.ssa, nir_src_for_ssa(sysval));
 131       nir_instr_remove(&load_var->instr);
 132
 133       state->progress = true;
 134    }
 135
 136    return true;
 137 }
 138
 139 static bool
 140 convert_impl(nir_function_impl *impl)
 141 {
 142    struct lower_system_values_state state;
 143
 144    state.progress = false;
 145    nir_builder_init(&state.builder, impl);
 146
 147    nir_foreach_block(impl, convert_block, &state);
 148    nir_metadata_preserve(impl, nir_metadata_block_index |
 149                                nir_metadata_dominance);
 150    return state.progress;
 151 }
 152
 153 bool
 154 nir_lower_system_values(nir_shader *shader)
 155 {
 156    bool progress = false;
 157
 158    nir_foreach_function(shader, function) {
 159       if (function->impl)
 160          progress = convert_impl(function->impl) || progress;
 161    }
 162
 163    exec_list_make_empty(&shader->system_values);
 164
 165    return progress;
 166 }